Generally, most of apparatuses and devices including various devices requiring security such as an Automatic Teller Machine (ATM) of a bank, a safe open/close device, a computer, and a mobile communication terminal that need to set and release a password, input a separately provided button key or a password via a password input screen prepared in a separately provided display unit.
More particularly, a mobile communication terminal requires a password when a user initially enters the mobile terminal, but as electronic communication industries develop, the user is requested to input password even when the user desires to use relevant contents, enter a desired Internet site, or download a relevant file.
In more detail, a mobile communication terminal has various additional functions besides a basic communication function. For example, the mobile communication terminal mounts a phonebook function, an electronic scheduler, an Internet access, games, music reproduction, etc. thereon. For the phonebook function or electronic scheduler, the mobile communication terminal is configured to set a password so that information thereof cannot be read. In addition, in case of user information or voice reproduction, password setting is required. In this example, exposure of a password causes a very important problem such as infringement of personal privacy.
As a specific example, when a mobile communication terminal requires input of a password, a controller of the mobile terminal actually displays a visual keyboard when the mobile communication terminal has a touch screen, and requires a user to input a password using the visual keyboard. In this example, the user sequentially inputs relevant numbers or combination of numbers and characters of four digits or more while viewing the keyboard. A frequent password input in a public place where other people may view by the side has a problem of exposing personal information. Accordingly, inconvenience of having to frequently change a password is caused.